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/*
* Mediated device Core Driver
*
* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
* Author: Neo Jia <cjia@nvidia.com>
* Kirti Wankhede <kwankhede@nvidia.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/uuid.h>
#include <linux/sysfs.h>
#include <linux/mdev.h>
#include "mdev_private.h"
#define DRIVER_VERSION "0.1"
#define DRIVER_AUTHOR "NVIDIA Corporation"
#define DRIVER_DESC "Mediated device Core Driver"
static LIST_HEAD(parent_list);
static DEFINE_MUTEX(parent_list_lock);
static struct class_compat *mdev_bus_compat_class;
static LIST_HEAD(mdev_list);
static DEFINE_MUTEX(mdev_list_lock);
static int _find_mdev_device(struct device *dev, void *data)
{
struct mdev_device *mdev;
if (!dev_is_mdev(dev))
return 0;
mdev = to_mdev_device(dev);
if (uuid_le_cmp(mdev->uuid, *(uuid_le *)data) == 0)
return 1;
return 0;
}
static bool mdev_device_exist(struct mdev_parent *parent, uuid_le uuid)
{
struct device *dev;
dev = device_find_child(parent->dev, &uuid, _find_mdev_device);
if (dev) {
put_device(dev);
return true;
}
return false;
}
/* Should be called holding parent_list_lock */
static struct mdev_parent *__find_parent_device(struct device *dev)
{
struct mdev_parent *parent;
list_for_each_entry(parent, &parent_list, next) {
if (parent->dev == dev)
return parent;
}
return NULL;
}
static void mdev_release_parent(struct kref *kref)
{
struct mdev_parent *parent = container_of(kref, struct mdev_parent,
ref);
struct device *dev = parent->dev;
kfree(parent);
put_device(dev);
}
static
inline struct mdev_parent *mdev_get_parent(struct mdev_parent *parent)
{
if (parent)
kref_get(&parent->ref);
return parent;
}
static inline void mdev_put_parent(struct mdev_parent *parent)
{
if (parent)
kref_put(&parent->ref, mdev_release_parent);
}
static int mdev_device_create_ops(struct kobject *kobj,
struct mdev_device *mdev)
{
struct mdev_parent *parent = mdev->parent;
int ret;
ret = parent->ops->create(kobj, mdev);
if (ret)
return ret;
ret = sysfs_create_groups(&mdev->dev.kobj,
parent->ops->mdev_attr_groups);
if (ret)
parent->ops->remove(mdev);
return ret;
}
/*
* mdev_device_remove_ops gets called from sysfs's 'remove' and when parent
* device is being unregistered from mdev device framework.
* - 'force_remove' is set to 'false' when called from sysfs's 'remove' which
* indicates that if the mdev device is active, used by VMM or userspace
* application, vendor driver could return error then don't remove the device.
* - 'force_remove' is set to 'true' when called from mdev_unregister_device()
* which indicate that parent device is being removed from mdev device
* framework so remove mdev device forcefully.
*/
static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove)
{
struct mdev_parent *parent = mdev->parent;
int ret;
/*
* Vendor driver can return error if VMM or userspace application is
* using this mdev device.
*/
ret = parent->ops->remove(mdev);
if (ret && !force_remove)
return -EBUSY;
sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups);
return 0;
}
static int mdev_device_remove_cb(struct device *dev, void *data)
{
if (!dev_is_mdev(dev))
return 0;
return mdev_device_remove(dev, data ? *(bool *)data : true);
}
/*
* mdev_register_device : Register a device
* @dev: device structure representing parent device.
* @ops: Parent device operation structure to be registered.
*
* Add device to list of registered parent devices.
* Returns a negative value on error, otherwise 0.
*/
int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
{
int ret;
struct mdev_parent *parent;
/* check for mandatory ops */
if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
return -EINVAL;
dev = get_device(dev);
if (!dev)
return -EINVAL;
mutex_lock(&parent_list_lock);
/* Check for duplicate */
parent = __find_parent_device(dev);
if (parent) {
ret = -EEXIST;
goto add_dev_err;
}
parent = kzalloc(sizeof(*parent), GFP_KERNEL);
if (!parent) {
ret = -ENOMEM;
goto add_dev_err;
}
kref_init(&parent->ref);
mutex_init(&parent->lock);
parent->dev = dev;
parent->ops = ops;
if (!mdev_bus_compat_class) {
mdev_bus_compat_class = class_compat_register("mdev_bus");
if (!mdev_bus_compat_class) {
ret = -ENOMEM;
goto add_dev_err;
}
}
ret = parent_create_sysfs_files(parent);
if (ret)
goto add_dev_err;
ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
if (ret)
dev_warn(dev, "Failed to create compatibility class link\n");
list_add(&parent->next, &parent_list);
mutex_unlock(&parent_list_lock);
dev_info(dev, "MDEV: Registered\n");
return 0;
add_dev_err:
mutex_unlock(&parent_list_lock);
if (parent)
mdev_put_parent(parent);
else
put_device(dev);
return ret;
}
EXPORT_SYMBOL(mdev_register_device);
/*
* mdev_unregister_device : Unregister a parent device
* @dev: device structure representing parent device.
*
* Remove device from list of registered parent devices. Give a chance to free
* existing mediated devices for given device.
*/
void mdev_unregister_device(struct device *dev)
{
struct mdev_parent *parent;
bool force_remove = true;
mutex_lock(&parent_list_lock);
parent = __find_parent_device(dev);
if (!parent) {
mutex_unlock(&parent_list_lock);
return;
}
dev_info(dev, "MDEV: Unregistering\n");
list_del(&parent->next);
class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
device_for_each_child(dev, (void *)&force_remove,
mdev_device_remove_cb);
parent_remove_sysfs_files(parent);
mutex_unlock(&parent_list_lock);
mdev_put_parent(parent);
}
EXPORT_SYMBOL(mdev_unregister_device);
static void mdev_device_release(struct device *dev)
{
struct mdev_device *mdev = to_mdev_device(dev);
dev_dbg(&mdev->dev, "MDEV: destroying\n");
kfree(mdev);
}
int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid)
{
int ret;
struct mdev_device *mdev;
struct mdev_parent *parent;
struct mdev_type *type = to_mdev_type(kobj);
parent = mdev_get_parent(type->parent);
if (!parent)
return -EINVAL;
mutex_lock(&parent->lock);
/* Check for duplicate */
if (mdev_device_exist(parent, uuid)) {
ret = -EEXIST;
goto create_err;
}
mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
if (!mdev) {
ret = -ENOMEM;
goto create_err;
}
memcpy(&mdev->uuid, &uuid, sizeof(uuid_le));
mdev->parent = parent;
kref_init(&mdev->ref);
mdev->dev.parent = dev;
mdev->dev.bus = &mdev_bus_type;
mdev->dev.release = mdev_device_release;
dev_set_name(&mdev->dev, "%pUl", uuid.b);
ret = device_register(&mdev->dev);
if (ret) {
put_device(&mdev->dev);
goto create_err;
}
ret = mdev_device_create_ops(kobj, mdev);
if (ret)
goto create_failed;
ret = mdev_create_sysfs_files(&mdev->dev, type);
if (ret) {
mdev_device_remove_ops(mdev, true);
goto create_failed;
}
mdev->type_kobj = kobj;
dev_dbg(&mdev->dev, "MDEV: created\n");
mutex_unlock(&parent->lock);
mutex_lock(&mdev_list_lock);
list_add(&mdev->next, &mdev_list);
mutex_unlock(&mdev_list_lock);
return ret;
create_failed:
device_unregister(&mdev->dev);
create_err:
mutex_unlock(&parent->lock);
mdev_put_parent(parent);
return ret;
}
int mdev_device_remove(struct device *dev, bool force_remove)
{
struct mdev_device *mdev, *tmp;
struct mdev_parent *parent;
struct mdev_type *type;
int ret;
bool found = false;
mdev = to_mdev_device(dev);
mutex_lock(&mdev_list_lock);
list_for_each_entry(tmp, &mdev_list, next) {
if (tmp == mdev) {
found = true;
break;
}
}
if (found)
list_del(&mdev->next);
mutex_unlock(&mdev_list_lock);
if (!found)
return -ENODEV;
type = to_mdev_type(mdev->type_kobj);
parent = mdev->parent;
mutex_lock(&parent->lock);
ret = mdev_device_remove_ops(mdev, force_remove);
if (ret) {
mutex_unlock(&parent->lock);
mutex_lock(&mdev_list_lock);
list_add(&mdev->next, &mdev_list);
mutex_unlock(&mdev_list_lock);
return ret;
}
mdev_remove_sysfs_files(dev, type);
device_unregister(dev);
mutex_unlock(&parent->lock);
mdev_put_parent(parent);
return 0;
}
static int __init mdev_init(void)
{
int ret;
ret = mdev_bus_register();
/*
* Attempt to load known vfio_mdev. This gives us a working environment
* without the user needing to explicitly load vfio_mdev driver.
*/
if (!ret)
request_module_nowait("vfio_mdev");
return ret;
}
static void __exit mdev_exit(void)
{
if (mdev_bus_compat_class)
class_compat_unregister(mdev_bus_compat_class);
mdev_bus_unregister();
}
module_init(mdev_init)
module_exit(mdev_exit)
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
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